Microporous membrane air freshening device

ABSTRACT

There is described a device comprising a base with at least one volatile active housed in a reservoir, at least one wall of which comprises a wicking membrane. In particular there is described a device which is a liquid air freshener.

This invention relates to a novel device incorporating a microporousmembrane.

More particularly the invention relates to a novel air freshening deviceor a devices for releasably storing a volatile active agent.

Conventional liquid air fresheners generally comprise a reservoircontaining a fragrance solution, into which dips a wick, which isconnected to an emanating surface. The perfume solution travels up thewick to the emanating surface from which the perfume evaporates andfreshens the surrounding atmosphere. In many examples the wick andemanating surface are formed from the same item. The fragrance solutionmay be a true solution (comprising a perfume base and a solvent that ismiscible with the perfume base) or a colloidal solution (comprisingperfume base, water, a surfactant which solubilises the perfume in thewater, and optionally solvents).

One disadvantage of conventional liquid air fresheners is that thefragrance solution can leak from the packaging should the device beaccidentally knocked over. This imposes certain limitations with regardshow the product is used, and the types of design forms that the productcan take.

More recently air freshening devices incorporating hydrophobic polymericmembranes have been developed. U.S. Pat. No. 4,145,001, to American CanCo. describes a volatile deodoriser sandwiched between the layers of alaminate material.

International Patent Application No. WO 98/23304, to Burgopack Stampadescribes a container for volatile substances comprising a plurality(five) of outer impermeable plies, detachable from a permeable ply.

U.S. Pat. No. 5,804,264 to American National Can Co. describes amultilayer permeable membrane for use in air fresheners comprising lowdensity polyethylenes.

Such devices comprise a fragrance composition contained within a sealedreservoir. At least one wall of the reservoir comprises a membrane, forexample, which is constructed from a material that is permeable toperfume vapours. However, such devices suffer from the disadvantage thatthe water is unable to migrate through the membrane and thus the liquid,or gel, compositions used in such devices are essentially anhydrous. Thecompositions generally comprise a perfume base and, optionally, avolatile solvent and, optionally, a small amount of a thickening agent,such as, a fumed silica or ethyl cellulose. The compositions, beingessentially free of water, tend to be relatively expensive.

Thus there has long been a need for a device which comprises a waterbased system but which does not suffer from the disadvantages of, interalia, leaking, as hereinbefore described.

Teslin® (origin: PPG Industries) is described in U.S. Pat. No. 4,861,644and comprises a single layer, highly filled, microporous film and isconventionally used as a synthetic printing sheet. Teslin® isessentially a matrix of linear ultrahigh molecular weight polyolefin avery large proportion of finely divided particulate siliceous filler,and a high void content microporous material.

More specifically, although different grades of Teslin® are available,Teslin® generally comprises a polyolefin which contains approximately60% w/w non-abrasive filler. The structure is approximately 65% v/v air.Teslin® can be fusion bonded by impulse sealing to variousthermoplastics and certain thermosets.

Teslin® is generally known to be useful as a material for, e.g. labelprinting.

We have now surprisingly discovered that certain known microporousmaterials, such as Teslin®, can be used to construct a membrane for usein, for example, an aqueous based liquid air freshening device. Suchmaterials are especially advantageous in that they are capable ofsimultaneously acting as both a microporous membrane and a wick.Moreover, materials, such as Teslin® possess the ability to wick alongthe plane of the membrane.

Thus, according to a first aspect of the invention we provide a devicecomprising a base with at least one volatile agent active housed in areservoir, at least one wall of which comprises a wicking membrane.

More particularly we provide a device according to claim 1 characterisedin that the device is a liquid air freshener which comprises a perfumedair freshener base housed in a reservoir, at least one wall of whichcomprises a wicking membrane. Preferentially, the perfumed air freshenerbase is an aqueous system.

By the term wicking membrane we especially mean a membrane which iscapable of performing a wicking action in the plane of the membrane.

It will be understood that the device of the invention may suitably beused for air freshening or other similar functions. Thus, the volatileactive agent may be selected from an insecticide, an insect repellent,an insect attractant, a fragrance, a deodorising agent and ananti-bacterial agent, or any combination thereof

Thus according to a preferred feature of the invention we provide aliquid air freshener which comprise an aqueous perfumed air freshenerbase housed in a reservoir, at least one wall of which comprises amicroporous membrane which membrane comprises a matrix of linearultrahigh molecular weight polyolefin. a very large proportion of finelydivided particulate siliceous filler, and a high void content.

In a preferred embodiment of the invention the microporous membrane maycomprise Teslin®.

The thickness of the membrane may vary and may be for example, from 0.05to 2.0 mm thick, preferably from 0.7 to 1.8 mm, more preferably from 0.8to 1.4 mm, e.g. 1.0 mm thick.

The remaining walls of the reservoir may comprise any conventionallyknown material, for example, a plastics material. Any conventionallyknown plastic material may be used, such as, for example, ofpolyethylenes, polypropylene, polymethyl methacrylate, ABS, polystyrene,rigid PVC, PMMA, Polyester and polycarbonate. A preferred material is apolyolefin, e.g. polypropylene.

Alternatively, the plastics material may comprise a laminate material.Such a laminate may comprise any of the aforementioned materials. In afurther embodiment the laminate may comprise one or more of theaforementioned materials bonded to a more robust material such as glass,ceramic, metal, wood, stone, etc.

Preferentially, the reservoir surface, or at least an edge of thesurface, may comprise a weldable material, thus facilitating welding tothe membrane. Examples of such weldable materials include, but shall notbe limited to polyethylenes, polypropylene, polyethylene orpolypropylene laminates, such as PET/PE laminates, PET/PP laminates andBarex/PE laminates.

The Teslin® may be fusion bonded to, for example, a flat panel samplesof polyethylenes, polypropylene, polymethyl methacrylate, ABS,polystyrene, rigid PVC, polycarbonate, Barex, PET and Plexiglas.

Alternatively, the Teslin may be attached by other means, such as butnot limited to a suitable adhesive, or it may be compressed between thecontainer and a restraining collar through for example but not limitedto a screw or clipping mechanism in the collar and/or container.

The perfume solution may be a conventional aqueous compositioncomprising water, at least one surfactant, a perfume base and optionallyone or more solvents.

The perfume solution may generally comprise between 0.01% to 100% w/w ofperfume, 0.01% to 99.99% w/w of water, 0.01% to 40% w/w of one or moresuitable surfactants and optionally 0.01% to 99.99% w/w of one or moresuitable solvents. Usually the concentration of perfume is between 8 and20% by weight, often about 10% by weight.

Alternatively it may be an aqueous, surfactant free composition such asthose described in U.S. Pat. No. 4,663,081 or U.S. Pat. No. 6,180,595incorporated herein by reference.

Alternatively, it may be a composition consisting of 100% fragrance orof fragrance and solvent only.

The microporous structure of the Teslin® absorbs the perfume solution,which can then evaporate to the surrounding atmosphere. Further, themicroporous properties of Teslin® facilitate wicking inside the membraneensuring that the evaporative surface area remains saturated withperfume solution throughout the life of the product thus guaranteeingconsistent fragrance intensity over the lifetime of the product.Furthermore, even when used in an inverted orientation with the Teslin®downwards, the perfume solution does not drip or leak from the device.

In yet a further embodiment of the invention the reservoir may beprovided with a wicking means. The wicking means may comprise aconventional wicking member, e.g. a central wick which abuts themembrane surface. Alternatively, the wicking means may comprise one ormore capillary grooves in the wall of the reservoir. In a yet furtheralternative, the wicking means may comprise an inner liner in thereservoir, which may be a hard sleeve or a self expanding film, forexample, the inner sleeve/film may rest on the floor of the reservoirand abut the inner surface of the membrane or the inner sleeve/film mayhave its ends bent inwards to have a wider surface that rests on thefloor of the reservoir and abuts against the inner surface of themembrane. This would improve the wicking action of the sleeve/film. Theinner sleeve/film may be continuous or discontinuous, whereby the endsof the discontinuous sleeve/film may overlap or be short of each other.

To prevent the fragrance solution from evaporation prior to activationby the consumer, the Teslin® membrane may be covered with a barriermaterial, such as but not limited to PE, PA, PP, PET, Barex, Nylon,Aluminium or a laminate comprising but not limited to one or more ofthese materials. Such barrier material may be weakly bonded to theTeslin® material through for example a fusion bond or weld, a suitableadhesive or a special release layer such as described in the previouslydescribed patents: U.S. Pat. No. 4,145,001, to American Can Co;International Patent No. WO 98/23304, to Burgopack Stampa; and U.S. Pat.No. 5,804,264 to American National Can Co. Alternatively, the barriermaterial may be weakly bonded to the Teslin® material at certain pointsonly, for example the edge.

According to a further aspect of the invention we provide a lavatorycleanser/deodoriser comprising a device as hereinbefore described.

We further provide an insecticide, insect attractant, insect repellent,deodoriser, germ killer comprising a device as hereinbefore described.

In an additional aspect of the invention we provide a device comprisinga base with at least one non-volatile active housed in a reservoir, atleast one wall of which comprises a wicking membrane.

In such a device at least one of the non-volatile materials is selectedfrom but not limited to a surfactant, a colouring agent, ananti-bacterial agent, an acid, a bleach, a solvent and a thickeningagent.

We further provide a method of manufacturing a device as hereinbeforedescribed which comprises fusion bonding, gluing or compressing amembrane to a plastics reservoir which reservoir is adapted to house adevice.

In a preferred method of the invention the microporous membranecomprises Teslin®.

We also provide the use of a microporous membrane comprising a matrix oflinear ultrahigh molecular weight polyolefin, a very large proportion offinely divided particulate siliceous filler, and a high void content inthe manufacture of a device as hereinbefore described.

In a preferred aspect of the invention we provide the use of theinvention wherein the membrane comprises Teslin®.

The invention will now be described by way of example only and withreference to the accompanying drawings.

FIG. 1 shows a diagram of a liquid air freshening device that comprisesa moulded polypropylene reservoir, to which is fusion bonded a Teslin®microporous film;

FIG. 2 is a schematic representation of an inverted reservoir;

FIG. 2 b is a schematic representation of a Teslin® film fusion bondedto a polypropylene film;

FIG. 3 is a schematic representation of a reservoir provided with acentral wick;

FIGS. 4 a to 4 d are schematic representations showing capillariedwalls;

FIG. 5 a to 5 b are schematic representation of a reservoir providedwith an inner film or sleeve;

FIG. 6 is a schematic representation of a constraining collarcompressing the Teslin® film to the reservoir;

FIG. 7 is a schematic representation of a reservoir in which a barrierfilm is held on the Teslin® film by a weldable material; and

FIG. 8 is a schematic representation of a reservoir in which a barriermaterial is held on the Teslin® film by an adhesive or a special releaselayer.

Referring to FIG. 1, a plastics, e.g. polypropylene, reservoir (1)comprises one wall (2), e.g. the front wall, which is a Teslin®membrane. The membrane is fusion bonded to the walls of the reservoir.Preferentially, the base of the reservoir is provided with a lip (3) atthe end of the front face, enabling the reservoir to stand vertically byresting on the lip and the rear of the base. In use, the reservoir maybe filled, or partially filled, with a liquid air freshener (4).

Referring to FIGS. 2 and 2 b, a reservoir may be inverted and theTeslin® film does not leak the perfume solution. The Teslin® film may befilm fusion bonded (5) to the polypropylene reservoir.

Referring to FIG. 3, a reservoir may have the membrane at the top and toensure continuous feeding of the membrane the performance of the airfreshener may be improved by incorporating a central wicking member (6)into the reservoir.

Referring to FIGS. 4 a to 4 d, as an alternative to the central wickingmember, the inner surface of the reservoir walls may be provided with aplurality of capillaries (7) which facilitate the transfer of theperfume solution to the membrane surface.

Referring to FIGS. 5 a and 5 b, the reservoir may be provided with aninner liner (9) in the form of a sleeve or a film. The inner liner (i.e.sleeve/film) sits on the base of the reservoir and the distal end of theliner abuts the inner membrane surface. Thus, the capillary action (8)of the liner transports the perfume solution to the inner membranesurface. Alternatively, the liner may be a sheet or film that isinserted into the outer container and forced into the shape by the outercontainer, thus lining the inside wall of the outer container. In thisway the two ends of the sheet may overlap or be short of each other. Thetips of the liner (10) may be bent inwards to improve wicking action.

Referring to FIG. 6, the reservoir may be attached to a collar (11) viaa screw or clipping mechanism that compresses the Teslin® film againstthe reservoir, sealing the reservoir and preventing leakage at the edge.

Referring to FIGS. 7 and 8 a barrier material (12) is fixed to theTeslin® film (2) by the use of a circumferential strip of weldablematerial (13). In FIG. 8 the weldable material is replaced by a weaklybonded adhesive or special release layer (14).

1. A device comprising a base with at least one volatile active agenthoused in a reservoir, at least one wall of which comprises a wickingmembrane.
 2. A device comprising a base with at least one non-volatileactive housed in a reservoir, at least one wall of which comprises awicking membrane.
 3. A device according to claims 1 characterised inthat the device is a liquid air freshener which comprises a perfumed airfreshener base housed in a reservoir, at least one wall of whichcomprises a wicking membrane.
 4. A device according to claim 1characterised in that the active volatile material is selected from aninsecticide, and insect repellent, an insect attractant, a fragrance, adeodorising agent and an anti-bacterial agent, or any combinationthereof.
 5. A device according to claim 1, characterised in that theperfumed air freshener is an aqueous perfumed air freshener.
 6. A deviceaccording to claim 1 characterised in that the membrane comprises amatrix of linear ultrahigh molecular weight polyolefin, a very largeproportion of finely divided particulate siliceous filler, and a highvoid content.
 7. A device according to claim 6 characterised in that themicroporous membrane comprises Teslin®.
 8. A device according to claim 1characterised in that the thickness of the membrane is from 0.05 to 2.0mm.
 9. A device according to claim 8 characterised in that the thicknessof the membrane is from 0.7 to 1.8 mm.
 10. A device according to claim 9characterised in that the thickness of the membrane is from 0.7 to 1.4mm.
 11. A device according to claim 1 characterised in that theremaining walls of the reservoir comprise a plastics material.
 12. Adevice according to claim 11 characterised in that the plastics materialis selected from one or more of polyethylene, polypropylene, polymethylmethacrylate, ABS, polystyrene, rigid PVC, polycarbonate, Barex, PET andPlexiglas.
 13. A device according to claim 1 characterised in that thereservoir comprises a laminate material.
 14. A device according to claim13 characterised in that the laminate comprises a plastics materialbonded to a glass, ceramic, wood, stone, porcelain, etc.
 15. A deviceaccording to claim 13 characterised in that the reservoir surface, or atleast an edge of the surface, comprises a weldable or fusable material.16. A device according to claim 15 characterised in that the weldable orfusable material is a polyethylene laminates.
 17. A device according toclaim 16 characterised in that the laminate is selected from PET/PElaminate and Barex/PE laminate.
 18. A device according to claim 12characterised in that the plastics material is polypropylene.
 19. Adevice according to claim 1 characterised in that the membrane is fusionbonded to the reservoir.
 20. A device according to claim 1 characterisedin that the membrane is attached to the reservoir by other means, suchas but not limited to a suitable adhesive or restraining collar.
 21. Adevice according to claim 1 characterised in that the reservoir isprovided with a wicking means.
 22. A device according to claim 21characterised in that the wicking means comprises a central wick whichabuts the membrane surface.
 23. A device according to claim 21characterised in that the wicking means comprises one or morecapillaries in the wall of the reservoir.
 24. A device according toclaim 23 characterised in that the wicking means comprises one or morecapillary grooves or tubes in the wall of the reservoir.
 25. A deviceaccording to claim 21 characterised in that the wicking means comprisesa continuous, overlapping or interrupted inner sleeve in the reservoir.26. A device according to claim 25 characterised in that the innersleeve contains one or more capillaries.
 27. A device according to claim23 characterised in that the inner sleeve contains one or morecapillaries, grooves or tubes.
 28. A device according to claim 1characterised in that the concentration of perfume is in the range offrom 0.01% to 100% w/w.
 29. A device according to claim 1 characterisedin that the perfume solution comprises water, at least one surfactant, aperfume base and, optionally, one or more solvents.
 30. A deviceaccording to claim 29 characterised in that the perfume solutioncomprises between 5 and 30% by weight of perfume.
 31. A device accordingto claim 30 characterised in that the perfume solution comprises between8 and 20% by weight of perfume.
 32. A device according to claim 31characterised in that the perfume solution comprises about 10% by weightof perfume.
 33. A device according to claim 1 characterised in that theperfume solution is an aqueous, surfactant free composition.
 34. Adevice according to claim 1 characterised in that the perfume solutionis blend of perfume and one or more solvents.
 35. (canceled)
 36. Alavatory cleanser/deodoriser comprising a device according to claim 1.37. An insecticide, insect attractant, insect repellent, deodoriser,germ killer comprising a device according to claim
 1. 38. A deviceaccording to claim 2 characterised in that at least one of thenon-volatile materials is selected from but not limited to a surfactant,a colouring agent, an anti-bacterial agent, an acid, a bleach, a solventand a thickening agent.
 39. A device according to claim 38 characterisedin that at least one of the non-volatile materials is water soluble. 40.A lavatory cleanser/deodoriser comprising a device according to claim 2.41. An insecticide, insect attractant, insect repellent, deodoriser,germ killer comprising a device according to claim
 2. 42. A method ofmanufacturing a device according to claim 1 which comprises fusionbonding, gluing or compressing a membrane to a plastics reservoir whichreservoir is adapted to house a device.
 43. A method according to claim42 characterised in that the microporous membrane comprises Teslin®. 44.The use of a microporous membrane comprising a matrix of linearultrahigh molecular weight polyolefin, a very large proportion of finelydivided particulate siliceous filler, and a high void content in themanufacture of a device according to claim
 1. 45. The use according toclaim 44 characterised in that the membrane comprises Teslin®.
 46. Adevice according to claim 1 characterised in that the membrane is sealedwith a film member.
 47. A device according to claim 46 characterised inthat the membrane is sealed with a film member using one or more of anadhesive, a special release layer or a thermosetting material. 48.(canceled)
 49. A device substantially as described with reference to theaccompanying drawings and examples.